User blog comment:FluffyMermaid78/The PBB theme was in a core game series game?!/@comment-31267872-20180526142112

Lots of music in PBB is taken from or based off of the core series music. Route 9's music was very similar to Eterna Forest (I like Eterna Forest better because it has a flute or something). The battle music in the Colosseum is directly taken from, well, Pokémon Colosseum.

You can never replace the best music from the core series, though...*cough* Gen 4 and Gen 5